Junction clamp for electric wires



June 23, 1936.

C E. CHATFIELD JUNCTION CLAMP FOR ELECTRIC WIRES Filed April 4, 1929 //r7// WI /7 IN VN TOR. 67a ren 0e E. 67262 Zfild Gama/W0 A TTORNEYS Patented June 23, 1936 UNITED STATES PATENT OFFICE JUNCTIQN CLAMP FOR ELECTRIC WIRES Clarence E.

Chatfield, Indianapolis, Ind., as-

Application April 4, 1929, Serial No. 352,350

8 Claims.

My invention relatesto improvements in connector clamps for electric wires and is particularly adapted for taking a lead from a transmission wire to power consuming units.

The usual practice in connection with transmission wires, and particularly high tension transmission wires is to tap these wires where it is desired to lead the power therefrom to power houses, power consuming units and the like.

More frequently these taps are taken from the transmission line and lead to a transformer which 'is adapted to step down the voltage and from which the lead or leads go to the power consuming unit or units.

16 The transmission line is usually formed of aluminum, while the tap conductor is usually formed of copper. Either the conductor must be formed of copper or it must ,have at its connector end a copper joint of some character in order that the connection from the transformer or power unit be made copper to copper as these units are provided with copper terminals.

! In order to connect the tap to the transmission line, clamps are provided, adapted to clamp on to the transmission line and provided with clamping means also adapted to clamp to the secondary or tap line.

My invention relates particularly to this type of clamp and. is designed to provide the most effective electrical connection between the two lines, which connection will resist corrosion.

For the purpose of disclosing my invention, I have illustrated certain embodiments thereof in the accompanying drawing in which: I

Fig. 1 is a view of a transmission line showing certain applications of my clamp;

Fig. 2 is a side elevation of one form of clamp embodying my invention;

Fig. 3 is an end elevation thereof;

Fig. 4 is a transverse sectional view of the clamp shown in Fig. 2;

Fig. 5 is a plan view partially in section of a modified form of clamp and; I

Fig. 6 is a transverse sectional view of the clamp shown in Fig. 5.

In Fig. l, I have shown a transmission line I from which a tap lead 2 is taken, this lead being connected to the transmission line by the clamp 3, which is of the form illustrated in Figs. 2, 3,

and 4 and the lead 2 is shown as leading to a transformer 4. The line I which is of aluminum wire is also shown as being connected to an extension 5 which is of copper wire, suitable insulators 6 being interposed between the line I and 55 the extension 5 and a suitable cross-arm of a pole or the like I being provided for supporting the parts. In order to make the electrical connection between the line I and extension 5, I provide a jumper 8, which is connected at one end by a clamp 9 to the wire I, this clamp being of 5 the form shown in Figs. 5 and 6, and at its opposite end connected to the extension 5 by a similar clamp I0. I have shown the clamp II] as being used although this end of the jumper may, if desired, be soldered to the extension 5. 10

The clamp 3 comprises a base II having extending from one face thereof a pair of hooks I2 and I3, the hook ends of which are in alignment, but are extended in opposite directions. Cooperating with these hooks is a movable clamping 1:, jaw I I operated by a screw I5 extending through the base II. The base II is provided with tap sockets or openings I6 and I1, one of which extends vertically through the bottom and the other may extend horizontally therethrough. Coop- 20 erating with these sockets are set screws I8. In operation the hooks I2 and I3 take over the wire and the clamp I4 is moved to securely clamp the structure to the wire. The take-01f wire has one 'end socketed in either of the sockets I6 or II 5 being securely in position by either of the set screws I8. This clamp is made from bronze, brass or copper, bronze being preferable because of its strength and conductivity. However, where bronze or similar material makes a junction with 3 aluminum wire a form of electrolysis sets up which is commonly known in the art as a mutual corrosion. This, I understand, is due to the fact that each metal has a natural potential and where materials having unlike natural potentials are 5 connected, a mutual corrosion is set up as soon as moisture comes in contact with the joint.' It is desirable to use bronze for strength and furthermore, bronze has substantially the same natural potential as copper. Therefore, when the 40 copper lead is secured to the clamp mutual corrosion will not be set up. However, bronze has a different natural potential from aluminum and when bronze is used to make clamping contact with aluminum, natural corrosion is set up de- 45 stroying the contact and destroying the clamping member. I have discovered that the natural potential of chromium is substantially the same as that of aluminum and that, therefore, when chromium contacts with aluminum there is no natural corrosion set up. Therefore, the clamp ing member 3 or at least that portion of the surface thereof which makes clamping contact with the aluminum wire is electroplated with chromium, while that portion which comes in contactwith the copper wire is left unplated. In the particular form of clamp shown in Figs. 2, 3, and 4 the sockets i6 and I! are unplated, While the rest of the clamp is electroplated with chromium. As a result when clamping contact is made with the aluminum wire and socketing contact is made with the copper wire, corrosion is prevented even when the clamp is used in exposed positions.

In the structure illustrated in Figs. 2, 3, and 4, the body portion I9 is illustrated as being of bronze while the exterior surface is provided with a coating 20 of chromium plating. Commercially it is easier to chromium plate the entire clamp than to chromium plate merelythose portions thereof which make the clamping contact with the aluminum wire, but it is entirely feasible if desired to chromium plate merely the clamping surface of the hooks l2 and i3 and the clamp I4.

In Figs. 5 and 6, I have illustrated another form of clamping connector. This clamping connector can be used for the same purpose as that for which the structure illustrated in Figs. 2, 3, and 4 may be used or may be used in the manner illustrated in Fig. 1. In this structure I provide a pair of clamping plates 2| and 22 adapted to meet face to face and having longitudinally extending grooves 23 in their meeting faces. The plates are connected in clamping position by means of screws 24. One half of the clamp is chromium plated as at 25 while the other half, the clamping members, being formed of bronze, is left unplated so that, where it is desired to make a connection the chromium plated half may receive the aluminum 'wire and the unplated half may receive the copper wire.

It will be understood that while I have described the clamps as being formed of bronze, other commercial material may be used when desired.

I claim as my invention:

1. A connector clamp for connecting copper and aluminum electrical conductors, formed of copper alloy, and having a conductor engaging portion electroplated with chromium.

2. A connector clamp for connecting copper and aluminum electrical conductors having substantially different natural potential, said clamp being formed of copper alloy having a natural electrical potential substantially different from one of said conductors and substantially the same as the other conductor, and having a clamp engaging portion electroplated with chromium.

3. A connector clamp for connecting copper and aluminum electrical conductors, formed of copper alloy and having a conductor-engaging portion electroplated with chromium, and having a second conductor engaging clamping surface unplated. 5

4. A connector clamp for connecting two electrical conductors, one of which is formed of aluminum and the other of which is formed of copper, said clamp being formed of metal containing copper and having the connector engaging surface for the aluminum wire chromium plated.

5. A connector clamp element for mechani ly and electrically connecting a copper and an aluminum conductor, said clamp element being of a metal close to copper in the electrolytic series and having two conductor receiving pockets formed therein one of said pockets being electro plated with a metal close to aluminum in the electrolytic series to prevent electrolytic corrosion in said clamp for conductors as a result of the electrical connections between said clamp and said conductors.

, 6. A connector clamp element for mehanical ly and. electrically connecting a copper and an 2 aluminum conductor, said clamp element com prising a main metal body having two conductor receiving pockets, one of said pockets having a conductor receiving surface close to copper in the electrolytic series and the other of said 30 pockets being electro plated with a metal close to aluminum in the electrolytic series to pre- -vent electrolytic corrosion in said clamp or conductors as a result of the connections between said clamp and conductors. 35 7. In combination, a joint comprising aluminum and copper conductors and metallic clamping members therefor, said clamping members being constructed of a copper alloy provided with a metallic surface coating of a metal close to aluminum in the electrolytic series and different from the metals of which the clamping members are composed, said coating contacting with said aluminum conductor.

8. The combination with an aluminum conductor, of a metallic corrosion-resisting clamp, said clamp being constructed of a copper alloy provided with a surface coating of a metal close to aluminum in the electrolytic series and different from the metals of which the clamping members are composed, said coating contacting with said conductor.

CLARENCE E. CHATFIELD.

CERTIFICATE OF CORRECTION.

Patent No. 2,045,547. June 25, 1956,

CLARENCE E. CHA'I'FIELD! It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, second column, line 21, claim 5, for the word "for" read or; and that the said -Let-.

ters Patent should be read with this correction therein that the same may conform to the record of the casein the Patent Office.

Signed and sealed this 15th day of September, A. D. 1956.

Henry. Van Arsdale (Seal) Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION.

Patent NO. 2,045,547. 4 June 23, 1956" CLARENCE E. CHATFIELD/ It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, second column, line 21, claim 5, for the word "for" read or; and that the said -Let-.

ters Patent should be read with this correction therein that the same may conform to the record of the casein the Patent Office.

Signed and sealed this 15th day of September, A. D. 1956.

Henry Van Arsdale (Seal) Acting Commissioner of Patents. 

